package com.scott.ch030;

import java.util.HashMap;

/**
 * @author 黄后林
 * @version 1.0
 * @note
 * @date 2021-12-18 14:34:52
 */
public class RoleService {

    public static void main(String[] args) {

        HashMap<String,Integer> stu= new HashMap<>();
        stu.put("scott",21);

        // HashMap只能接收2个实参 你传3个实参就会报错
        // HashMap<String,Integer,Double> stu= new HashMap<>();


    }
}
